In considering whether it is only necessary to simply replace the dried earth in its original position, it should be determined whether the undisturbed portion of an embankment will support the weight when unaided by counterforts with a foundation in solid ground at the toe of the slope, trenches and drains upon the slopes, and perhaps a rough stone bed below the seat of the slip acting as an open drain over part or the whole of it. In any case provision must be made that there is no localization of water between the original embankment and the filling or the counterfort. In some soils, particularly those having seams of sand or silt, the slipped earth frequently becomes displaced in layers, and if allowed to remain, each bed will form a water seam upon which any stratum can slide, and then the earth may not be at rest until the slope is very flat. The removal of the whole mass is the cheapest remedy. The surface left bare by the slipped earth should be trimmed, and all fissures in it be filled so as to prevent any accumulation or lodgment of water, but the slipped earth should only be excavated in short lengths, as it may render support and keep part of the face covered, and it should be remembered that although the upper portion of the fallen earth may be the drier it may not be the most stable. The system of removing the slipped earth, erecting rough rubble walls at intervals of 20 to 30 feet projecting as far as the face of the original slope, and then filling the intervening space with the material that has slipped, when turned over and punned, has been successfully adopted. It is advisable to cover with turf the replaced earth in the slope, unless some other protection is supplied. When any signs of movement afterwards take place a few additional counterforts, which, may also be made to act as drains, will generally restore the equilibrium. This system relies upon preventing movement in earth by separating the masses of the slipped soil, and draining and supporting them in detail. The foundations of the counterforts must be in the solid ground and not merely below the seat of the slip. It may be impossible to drain the site of a slip or the soil that has moved without dividing it into portions, the chief object being to thoroughly drain the site and the slipped earth, so that it is practically encircled with drains and any water prevented from collecting in or upon it. When the land is of little value and a cutting is in a mountain or hill-side, it may be advisable to assist an extensive slip, provided it happens before any public works are opened for traffic; and to remove the earth by loosening it by the action of a stream of water until it slides away, as draining or supporting it may be insufficient. Under such circumstances it is the best course to adopt, especially if a stream of water can be readily diverted to it as the unstable soil is finally disengaged. CHAPTER IV.